From 47d027147694fde94dd73305ee53b6a136cbeced Mon Sep 17 00:00:00 2001 From: Jon Maloy Date: Tue, 9 May 2023 10:29:03 -0400 Subject: [PATCH 08/15] apic: disable reentrancy detection for apic-msi RH-Author: Jon Maloy RH-MergeRequest: 277: memory: prevent dma-reentracy issues RH-Bugzilla: 1999236 RH-Acked-by: Thomas Huth RH-Acked-by: Miroslav Rezanina RH-Commit: [8/12] 25c3cf99b00cd9adc10d6e7afa9c3e3b7da08de2 (redhat/rhel/src/qemu-kvm/jons-qemu-kvm-2) Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1999236 Upstream: Merged CVE: CVE-2021-3750 commit 50795ee051a342c681a9b45671c552fbd6274db8 Author: Alexander Bulekov Date: Thu Apr 27 17:10:13 2023 -0400 apic: disable reentrancy detection for apic-msi As the code is designed for re-entrant calls to apic-msi, mark apic-msi as reentrancy-safe. Signed-off-by: Alexander Bulekov Reviewed-by: Darren Kenny Message-Id: <20230427211013.2994127-9-alxndr@bu.edu> Signed-off-by: Thomas Huth Signed-off-by: Jon Maloy --- hw/intc/apic.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/hw/intc/apic.c b/hw/intc/apic.c index 3df11c34d6..a7c2b301a8 100644 --- a/hw/intc/apic.c +++ b/hw/intc/apic.c @@ -883,6 +883,13 @@ static void apic_realize(DeviceState *dev, Error **errp) memory_region_init_io(&s->io_memory, OBJECT(s), &apic_io_ops, s, "apic-msi", APIC_SPACE_SIZE); + /* + * apic-msi's apic_mem_write can call into ioapic_eoi_broadcast, which can + * write back to apic-msi. As such mark the apic-msi region re-entrancy + * safe. + */ + s->io_memory.disable_reentrancy_guard = true; + s->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, apic_timer, s); local_apics[s->id] = s; -- 2.37.3